Twenty-one of the police officers face life terms if found guilty of taking part in the failed coup.
They are all accused of following Fetullah Gulen as well as failing to follow orders and carry out their duty to protect the president.
The trial began amid high security at a large jail complex on the outskirts of Istanbul, and is expected to last four days.
The police officers are the first set to face charges after a mass clampdown that led to the arrest of about forty thousand people in the wake of the failed coup in July.
The government of President ERDOGAN blamed US-based Islamic cleric FETULLAH GULEN for the coup plot; but that has been denied.
The Turkish government has also blamed the group for the assassination of Russian ambassador ANDREI KARLOV last week by an off-duty policeman.
